[llvm] r280147 - [COFFObjectFile] Ignore broken symbol table

[David Majnemer via llvm-commits]

Author: majnemer
Date: Tue Aug 30 15:20:24 2016
New Revision: 280147

URL: http://llvm.org/viewvc/llvm-project?rev=280147&view=rev
Log:
[COFFObjectFile] Ignore broken symbol table

When binaries are compressed by UPX, information about symbol table
offset and symbol count remain unchanged (but became invalid due to
compression).
This causes failure in the constructor and the rest of the binary cannot
be processed.

Instead, reset symbol related information (symbol/string table pointers,
sizes) - this should disable the related iterators and functions while
the rest of the binary can still be processed.

Patch by Bandzi Michal!

Modified:
    llvm/trunk/include/llvm/Object/COFF.h
    llvm/trunk/lib/Object/COFFObjectFile.cpp

Modified: llvm/trunk/include/llvm/Object/COFF.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/COFF.h?rev=280147&r1=280146&r2=280147&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/COFF.h (original)
+++ llvm/trunk/include/llvm/Object/COFF.h Tue Aug 30 15:20:24 2016
@@ -699,13 +699,18 @@ public:
       return COFFBigObjHeader->PointerToSymbolTable;
     llvm_unreachable("no COFF header!");
   }
-  uint32_t getNumberOfSymbols() const {
+  uint32_t getRawNumberOfSymbols() const {
     if (COFFHeader)
       return COFFHeader->isImportLibrary() ? 0 : COFFHeader->NumberOfSymbols;
     if (COFFBigObjHeader)
       return COFFBigObjHeader->NumberOfSymbols;
     llvm_unreachable("no COFF header!");
   }
+  uint32_t getNumberOfSymbols() const {
+    if (!SymbolTable16 && !SymbolTable32)
+      return 0;
+    return getRawNumberOfSymbols();
+  }
 protected:
   void moveSymbolNext(DataRefImpl &Symb) const override;
   Expected<StringRef> getSymbolName(DataRefImpl Symb) const override;

Modified: llvm/trunk/lib/Object/COFFObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/COFFObjectFile.cpp?rev=280147&r1=280146&r2=280147&view=diff
==============================================================================
--- llvm/trunk/lib/Object/COFFObjectFile.cpp (original)
+++ llvm/trunk/lib/Object/COFFObjectFile.cpp Tue Aug 30 15:20:24 2016
@@ -729,8 +729,12 @@ COFFObjectFile::COFFObjectFile(MemoryBuf
 
   // Initialize the pointer to the symbol table.
   if (getPointerToSymbolTable() != 0) {
-    if ((EC = initSymbolTablePtr()))
-      return;
+    if ((EC = initSymbolTablePtr())) {
+      SymbolTable16 = nullptr;
+      SymbolTable32 = nullptr;
+      StringTable = nullptr;
+      StringTableSize = 0;
+    }
   } else {
     // We had better not have any symbols if we don't have a symbol table.
     if (getNumberOfSymbols() != 0) {